Ar(h) · helion relative atomic mass

헬리온의 상대 원자 질량

Takeaway

The relative standard uncertainty fell by a factor of about 12 from the 1998 to the 2022 edition (2.9×10⁻¹⁰ → 2.5×10⁻¹¹): the error bars narrowed that much.
Of 6 earlier editions with a measured value, 3 have the 2022 value outside ±1σ (the error bar) and 2 outside ±2σ (the bar doubled); the normal expectation is about 1 in 3 and 1 in 22.
The largest move between editions came in 2014→2018, at 2.9 times the combined standard uncertainty of the two editions (|z| = 2.9).

Unit: none (dimensionless)
Note: Sensitivity candidate. Listed in the NIST tables as 'helion mass in u'.
M1: Half-life (years): 4.17 (2.21–37.07)

Value ±1σ by edition2022

Relative deviation from the 2022 value (symmetric-log axis). Open circles: the error bar does not reach the 2022 value. Squares: exact.

Editionyear of the recommended values (data cut-off)	As printedexactly as in the source table; digits in parentheses are the standard uncertainty in the last digits	Standard uncertaintyhalf-width of the error bar (±1σ)	Relative standard uncertaintystandard uncertainty ÷ \|value\|: bar width relative to the value	z vs previous editionmove from the previous edition ÷ combined standard uncertainty of the two	z vs 2022(2022 value − this value) ÷ this edition's standard uncertainty	Source locationpage and table of the paper, or file and line of NIST's table
1998	3.014 932 234 69(86)	8.6×10⁻¹⁰	2.9×10⁻¹⁰		14.2349	1998 ASCII:136
2002	3.014 932 2434(58)	5.8×10⁻⁹	1.9×10⁻⁹	1.4855	0.6090	2002 ASCII:137
2006	3.014 932 2473(26)	2.6×10⁻⁹	8.6×10⁻¹⁰	0.6136	−0.1415	2006 ASCII:138
2010	3.014 932 2468	2.5×10⁻⁹	8.3×10⁻¹⁰	−0.1386	0.0528	2010 ASCII:148
2014	3.014 932 246 73	1.2×10⁻¹⁰	4.0×10⁻¹¹	−0.0280	1.6833	2014 ASCII:148
2018	3.014 932 247 175	9.7×10⁻¹¹	3.2×10⁻¹¹	2.8840	−2.5052	2018 ASCII:155
2022	3.014 932 246 932	7.4×10⁻¹¹	2.5×10⁻¹¹	−1.9917		2022 ASCII:156